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neodymium magnets

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SM 25x275 [2xM8] / N42 - magnetic separator

magnetic separator

Catalog no 130294

GTIN: 5906301812876

5

Diameter Ø [±0,1 mm]

25 mm

Height [±0,1 mm]

275 mm

Weight

0.01 g

762.60 with VAT / pcs + price for transport

620.00 ZŁ net + 23% VAT / pcs

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SM 25x275 [2xM8] / N42 - magnetic separator

Specification/characteristics SM 25x275 [2xM8] / N42 - magnetic separator
properties
values
Cat. no.
130294
GTIN
5906301812876
Production/Distribution
Dhit sp. z o.o.
Country of origin
Poland / China / Germany
Customs code
85059029
Diameter Ø
25 mm [±0,1 mm]
Height
275 mm [±0,1 mm]
Weight
0.01 g [±0,1 mm]
Manufacturing Tolerance
± 0.1 mm

Magnetic properties of material N42

properties
values
units
coercivity bHc ?
860-955
kA/m
coercivity bHc ?
10.8-12.0
kOe
energy density [Min. - Max.] ?
318-334
BH max KJ/m
energy density [Min. - Max.] ?
40-42
BH max MGOe
remenance Br [Min. - Max.] ?
12.9-13.2
kGs
remenance Br [Min. - Max.] ?
1290-1320
T
actual internal force iHc
≥ 955
kA/m
actual internal force iHc
≥ 12
kOe
max. temperature ?
≤ 80
°C

Physical properties of NdFeB

properties
values
units
Vickers hardness
≥550
Hv
Density
≥7.4
g/cm3
Curie Temperature TC
312 - 380
°C
Curie Temperature TF
593 - 716
°F
Specific resistance
150
μΩ⋅Cm
Bending strength
250
Mpa
Compressive strength
1000~1100
Mpa
Thermal expansion parallel (∥) to orientation (M)
(3-4) x 106
°C-1
Thermal expansion perpendicular (⊥) to orientation (M)
-(1-3) x 10-6
°C-1
Young's modulus
1.7 x 104
kg/mm²

Shopping tips

The magnetic separator, namely the magnetic roller, uses the force of neodymium magnets, which are welded in a casing made of stainless steel usually AISI304. Due to this, it is possible to precisely segregate ferromagnetic elements from different substances. A key aspect of its operation is the use of repulsion of N and S poles of neodymium magnets, which allows magnetic substances to be attracted. The thickness of the magnet and its structure pitch determine the range and strength of the separator's operation.
Generally speaking, magnetic separators serve to extract ferromagnetic elements. If the cans are made from ferromagnetic materials, the separator will be able to separate them. However, if the cans are made of non-ferromagnetic materials, such as aluminum, the separator will not be able to separate them.
Yes, magnetic rollers find application in the food industry to remove metallic contaminants, for example iron fragments or iron dust. Our rods are constructed from durable acid-resistant steel, EN 1.4301, approved for use in food.
Magnetic rollers, often called magnetic separators, find application in food production, metal separation as well as waste processing. They help in eliminating iron dust in the course of the process of separating metals from other materials.
Our magnetic rollers are composed of a neodymium magnet embedded in a stainless steel tube cylinder made of stainless steel with a wall thickness of 1mm.
From both sides of the magnetic bar can be with M8 threaded holes - 18 mm, which enables quick installation in machines or magnetic filter drawers. A "blind" version is also possible in manual separators.
In terms of magnetic properties, magnetic bars differ in terms of magnetic force lines, flux density and the area of operation of the magnetic field. We produce them in materials, N42 as well as N52.
Usually it is believed that the stronger the magnet, the better. But, the strength of the magnet's power depends on the height of the used magnet and the quality of the material [N42] or [N52], as well as on the area of application and anticipated needs. The standard operating temperature of a magnetic bar is 80°C.
When the magnet is more flat, the magnetic force lines will be more compressed. Otherwise, when the magnet is thick, the force lines are longer and extend over a greater distance.
For making the casings of magnetic separators - rollers, most often stainless steel is employed, especially types AISI 304, AISI 316, and AISI 316L.
In a salt water contact, type AISI 316 steel is highly recommended due to its exceptional anti-corrosion properties.
Magnetic rollers are characterized by their specific arrangement of poles and their capability to attract magnetic substances directly onto their surface, in contrast to other devices that often use more complicated filtration systems.
Technical designations and terms related to magnetic separators comprise amongst others magnet pitch, polarity, and magnetic induction, as well as the type of steel used.
Magnetic induction for a magnet on a roller is determined using a teslameter or a gaussmeter with a flat Hall-effect probe, aiming to find the highest magnetic field value near the magnetic pole. The result is checked in a value table - the lowest is N30. All designations less than N27 or N25 suggest recycling that doesn't meet the standard - they are not suitable.
Neodymium magnetic rollers offer a range of benefits such as higher attracting power, longer lifespan, and effectiveness in separating fine metal particles. However, some of the downsides may involve the requirement for frequent cleaning, greater weight, and potential installation difficulties.
To properly maintain of neodymium magnetic rollers, it’s worth regularly cleaning them from deposits, avoiding extreme temperatures above 80 degrees, and shielding them from moisture if the threads are not sealed – in ours, they are. The rollers our rollers have waterproofing IP67, so if they are leaky, the magnets inside can rust and weaken. Testing of the rollers is recommended be carried out once every 24 months. Caution should be taken during use, as it’s possible getting pinched. If the protective tube is only 0.5 mm thick, it may wear out, which in turn could cause problems with the magnetic rod seal and product contamination. The range of the roller corresponds to its diameter: fi25mm gives an active range of about 25mm, while fi32 gives an active range of about 40mm.
A magnetic roller is a magnetic separator made from a neodymium magnet enclosed in a cylindrical stainless steel housing, which are used to remove metal contaminants from bulk and granular materials. They are used in the food industry, recycling, and plastic processing, where metal separation is crucial.

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their remarkable field intensity, neodymium magnets offer the following advantages:

  • They have stable power, and over more than ten years their attraction force decreases symbolically – ~1% (according to theory),
  • They remain magnetized despite exposure to magnetic noise,
  • Thanks to the polished finish and gold coating, they have an aesthetic appearance,
  • Magnetic induction on the surface of these magnets is very strong,
  • Neodymium magnets are known for very high magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the geometry),
  • Thanks to the freedom in shaping and the capability to adapt to specific requirements, neodymium magnets can be created in different geometries, which broadens their functional possibilities,
  • Significant impact in cutting-edge sectors – they are utilized in HDDs, electromechanical systems, medical equipment along with technologically developed systems,
  • Relatively small size with high magnetic force – neodymium magnets offer impressive pulling strength in compact dimensions, which makes them useful in small systems

Disadvantages of rare earth magnets:

  • They can break when subjected to a strong impact. If the magnets are exposed to shocks, we recommend in a steel housing. The steel housing, in the form of a holder, protects the magnet from breakage and additionally increases its overall durability,
  • They lose strength at extreme temperatures. Most neodymium magnets experience permanent degradation in strength when heated above 80°C (depending on the geometry and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
  • Due to corrosion risk in humid conditions, it is common to use sealed magnets made of plastic for outdoor use,
  • Limited ability to create internal holes in the magnet – the use of a external casing is recommended,
  • Possible threat due to small fragments may arise, if ingested accidentally, which is significant in the family environments. Moreover, miniature parts from these products may disrupt scanning after being swallowed,
  • High unit cost – neodymium magnets are pricier than other types of magnets (e.g., ferrite), which can restrict large-scale applications

Safety Precautions

The magnet is coated with nickel. Therefore, exercise caution if you have an allergy.

Studies clearly indicate a small percentage of people who suffer from metal allergies such as nickel. An allergic reaction often manifests as skin redness and rash. If you have a nickel allergy, try wearing gloves or avoid direct contact with nickel-plated neodymium magnets.

It is crucial not to allow the magnets to pinch together uncontrollably or place your fingers in their path as they attract to each other.

Magnets will jump and clash together within a distance of several to around 10 cm from each other.

Neodymium magnets are the most powerful magnets ever invented. Their strength can surprise you.

To use magnets properly, it is best to familiarize yourself with our information beforehand. This will help you avoid significant harm to your body and the magnets themselves.

Keep neodymium magnets away from the wallet, computer, and TV.

The strong magnetic field generated by neodymium magnets can damage magnetic media such as floppy disks, video tapes, HDDs, credit cards, magnetic ID cards, cassette tapes, etc. devices. They can also destroy devices like video players, televisions, CRT computer monitors. Do not forget to keep neodymium magnets away from these electronic devices.

Neodymium magnets should not be near people with pacemakers.

Neodymium magnets produce strong magnetic fields that can interfere with the operation of a heart pacemaker. However, if the magnetic field does not affect the device, it can damage its components or deactivate the device when it is in a magnetic field.

Magnets made of neodymium are highly delicate, they easily break as well as can crumble.

Magnets made of neodymium are extremely delicate, and by joining them in an uncontrolled manner, they will break. Neodymium magnets are made of metal and coated with a shiny nickel surface, but they are not as hard as steel. In the event of a collision between two magnets, there may be a scattering of fragments in different directions. Protecting your eyes is crucial in such a situation.

Dust and powder from neodymium magnets are flammable.

Do not attempt to drill into neodymium magnets. Mechanical processing is also not recommended. Once crushed into fine powder or dust, this material becomes highly flammable.

  Magnets are not toys, children should not play with them.

Remember that neodymium magnets are not toys. Be cautious and make sure no child plays with them. In the case of swallowing multiple magnets simultaneously, they can attract to each other through the intestinal walls. In the worst case scenario, this can lead to death.

Keep neodymium magnets as far away as possible from GPS and smartphones.

Strong fields generated by neodymium magnets interfere with compasses and magnetometers used in navigation, as well as internal compasses of smartphones and GPS devices.

Neodymium magnets can become demagnetized at high temperatures.

Although magnets have shown to retain their effectiveness up to 80°C or 175°F, this temperature may vary depending on the type of material, shape, and intended use of the magnet.

Safety precautions!

Please read the article - What danger lies in neodymium magnets? You will learn how to handle them properly.

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